1. Field of the Invention
This invention relates to a tape cutting mechanism for a tape printing apparatus, which is capable of cutting off a printed portion of a tape-shaped member sent out via a tape exit in response to a manual lever operation.
2. Prior Art
Conventionally, a tape cutting mechanism of this kind for a tape printing apparatus was proposed e.g. in Japanese Laid-Open Utility Model Publication (Kokai) No. 2-36450. This tape cutting mechanism includes a cutter holder having a hollow cylindrical shape and rotatably disposed for supporting a cutter blade, and a manual operation lever pivotally supported at a location close to a rotational axis of the cutter holder, for pivotal motion about a pivotal axis thereof. The cutter holder and the manual operation lever are arranged in the vicinity of a tape exit in a state mated with each other at a location close to their respective rotational and pivotal axes. Further, the cutter blade is supported in a state directed in the direction of a tangential line to the cutter holder, and constructed such that the cutter blade can cut through a tape-shaped member being sent out from the tape exit, from an orthogonal direction thereto. The manual operation lever largely protrudes outward from the apparatus, and when operated manually, the cutter holder is rotated via the mated portion to cause the cutter blade to perform a circular motion, whereby the tape-shaped member is cut through by force-cutting from the orthogonal direction.
In the conventional tape cutting mechanism constructed as above, since the tape-shaped member is cut through by a circular motion of the cutter blade, a component force is applied in a direction of rotation thereof as will entangle the tape-shaped member during cutting. As a result, a force from the manual operation lever is relieved although in a small amount. Therefore, a cutting force larger than necessary is required, and load is applied to the cutter blade as well, as reaction to the component force, so that the cutter blade is liable to be damaged as it is used over a longer time period. Further, although the manual operation lever, which largely protrudes out of the apparatus, can be easily operated by a small stroke, the apparatus is increase in size as a whole. If the manual operation lever is reduced in the amount of projection to decrease the size of the apparatus, however, sufficient stroke cannot be secured, so that the operation of the manual operation lever requires an increased force, thereby degrading the operability of the manual operation lever.
Recently, there is a demand for a tape printing apparatus of a small-sized handy type which allows the user to perform manual key operations, and a manual lever operation for cutting tape-shaped members while holding the apparatus with his hands. In this case, in view of the conventional construction of the tape cutting mechanism, it is considered very difficult to arrange both of an input portion of a cutter to which a force is applied for cutting operation of the cutter and a pivot of the manual operation lever in the vicinity of the tape exit, while ensuring the operability of the manual operation lever and reducing the size of the apparatus, and what is more, preventing a component force from being applied to the tape-shaped member.
It is an object of the invention to a tape cutting mechanism for a tape printing apparatus, which allows a user to operate a manual operation lever while holding the apparatus casing in his hands, with an excellent operability, thereby enabling a tape-shaped member to be cut efficiently.
To attain the above object, the present invention provides a tape cutting mechanism for a tape printing apparatus including a casing having a rear side surface, a rear corner portion, and a tape exit formed through the rear side surface, the tape cutting mechanism cutting off a printed portion of a tape-shaped member sent out via the tape exit, in response to a lever operation carried out in a state of the casing being held by hand.
The tape cutting mechanism according to the invention is characterized by comprising:
a cutter disposed to face the tape exit, for cutting the tape-shaped member from a direction orthogonal thereto, the cutter having an input portion for receiving a force applied thereto;
a manual operation lever pivotally supported in the rear corner portion of the casing, for causing the cutter to perform cutting operation, the manual operation lever having a rear end serving as a center of pivotal motion thereof, a front end serving as a force point to which a force is manually applied by the lever operation, and an intermediate portion located between the rear end and the front end, and extending along the casing from the rear end to the front end in a manner bent frontward; and
a pivot arm having one end for being engaged with the input portion of the cutter, another end serving as a center of pivotal motion thereof, and an intermediate portion located between the one end and the another end, and extending from the one end to the another end in a direction substantially orthogonal to a direction of cutting operation of the cutter, and
wherein the manual operation lever has an urging portion formed at the intermediate portion thereof, for abutting on the intermediate portion of the pivot arm and serving as a point of action for pivotally moving the pivot arm.
According to this tape cutting mechanism, when the manual operation lever is manually operated for pivotal motion by the front end portion thereof, the urging portion of the intermediate portion thereof abuts against the pivot arm to urge the same, whereby the pivot arm is pivotally moved about the other end thereof in a direction opposite to the direction of rotation of the pivotal motion of the manual operation lever. This causes the one end of the pivot arm to be engaged with the input portion of the cutter to transmit a force to the cutter for causing the same to perform a cutting operation. The cutter cuts through the tape-shaped member from a direction orthogonal to the tape-shaped member. The pivotal arm which serves as a driving force-transmitting system is interposed between the manual operation lever and the cutter, and hence even if a pivot of the manual operation lever and the input portion of the cutter are arranged close to the tape exit, it is possible to cut through the tape-shaped member from a truly orthogonal direction, thereby preventing a component force from being applied to the tape-shape member during cutting thereof. As a result, load applied to the cutter as a reaction can be reduced, thereby making it possible to enhance the durability of a blade of the cutter as well as to cut a printed tape to form a neat cut end face.
Further, since the intermediate portion of the pivot arm is pressed on by the intermediate portion of the manual operation lever by making use of the principles of the lever and fulcrum, it is possible to transmit the operating force applied to the manual operation lever to the input portion of the cutter with least reduction of the force, thereby directly applying the force to the cutter for the cutting operation thereof. Further, since the manual operation lever extends along the casing, it is possible to effectively arrange the manual operation lever to improve operability thereof and make the whole tape printing apparatus compact in size.
Preferably, the manual operation lever is bent such that the manual lever can be pivotally moved inwardly toward the casing by the force manually applied to the front end thereof.
According to this preferred embodiment, the lever operation of the manual operation lever can be ergonomically facilitated. More specifically, the manual operation lever may be configured such that the lever can be moved inwardly toward the casing, for a clockwise pivotal motion when it is designed to be operated by a finger of a user""s right hand, or for a counterclockwise pivotal motion when it is designed to be operated by a finger of a user""s left hand. This makes it possible to further enhance the operability of the manual operation lever.
Preferably, the tape cutting mechanism further includes a stopper against which the front end of the manual operation lever abuts when the cutter has reached a position at which the cutting operation is completed.
According to this preferred embodiment, the range of pivotal operation of the manual operation lever is limited, whereby the user can recognize by his sense that the tape-shaped member has been cut through. This prevents the lever from being pivotally moved than necessary, so that it is possible to enhance the operability and ease of handling of the lever, and further prevent damage of the operation lever itself due to pivotally moving operations. Although the casing may also play the role of the stopper, it is preferred that the stopper is formed as part of a frame of the tape printing apparatus, inside the casing.
Preferably, the cutter includes a cutter blade that is slid to cut through the tape-shaped member, and a cutter holder having one end having a holding portion for holding the cutter blade, and another end having the input portion engaged with the pivot arm, the cutter holder being configured such that the cutter holder can be slid in the direction of cutting operation.
According to this preferred embodiment, responsive to a force from the pivot arm, the cutter holder is slidingly moved in the direction of cutting operation, and the cutter blade held at the one end thereof cuts the tape-shaped member by force-cutting. This makes it possible to transmit the force to the cutter by a simple construction as well as to cut the tape-shaped member linearly. Further, since the cutter blade is a single blade, it is possible to reduce the number of components and the manufacturing costs of the whole tape printing apparatus. It should be noted that preferably, the cutter blade is constructed by an oblique blade whose cutting edge is slanted relative to the direction of sliding of the cutter. According to this construction, it is possible to reduce an area of contact between the cutter blade and the tape-shaped member to decrease the push-cutting force required for cutting operation and further enhance the durability of the cutter blade.
Preferably, the tape-shaped member is sent in a vertical attitude in which the tape-shaped member has a direction of width thereof set to a vertical direction, and the one end of the cutter holder has an upper end portion and a lower end portion at least one of which has resilience, the holding portion of the cutter holder comprising upper support portions formed on the upper end portion on respective front and rear surface sides of the cutter blade alternately along the direction of cutting operation, for holding an upper end of the cutter blade alternately from the front and rear surface sides thereof along the direction of cutting operation, and lower support portions formed on the lower end portion on the respective front and rear surface sides of the cutter blade alternately along the direction of cutting operation, for holding a lower end of the cutter blade alternately from the front and rear surface sides thereof along the direction of cutting operation, the holding portion resiliently holding the cutter blade vertically between the upper end portion and the lower end portion.
According to this preferred embodiment, the cutter blade is held from the front and rear side thereof such that the upper and lower end portions thereof are sandwiched alternately in the direction of cutting operation, which makes it possible to prevent cutting operation from causing vertical deflection of the cutter blade. Further, at the same time, the cutter blade is resiliently held by the cutter holder, so that the cutter blade can be easily attached to the cuter holder, and even when the cutter blade is worn or damaged, it can be easily replaced with a new one.
Preferably, the cutter holder further includes a cutter face-receiving portion which connects a proximal end portion of the upper end portion and a proximal end portion of the lower end portion to each other, and at the same time receives one of the front and rear side surfaces of the cutter blade.
According to this preferred embodiment, it is possible not only to facilitate mounting of the cutter blade by using the cutter face-receiving portion but also to prevent lateral deflection of the cutter blade during cutting operation. Therefore, even a thick tape-shaped member can be linearly cut through with stability. Further, it is preferred that part of the cutter face-receiving member is cut away to slant the same with respect to the direction of extension thereof, thereby imparting resilience to at least one of the upper support portions and the lower support portions.
Preferably, the casing has an abutment portion formed in a manner opposed to the cutter blade, and the tape cutting mechanism further includes a tape-retaining member that is slid in the direction of cutting operation in a manner interlocked with the lever operation of the manual operation lever to hold the tape-shaped member between the tape-retaining member and the abutment portion of the casing prior to an advancing operation of the cutter blade for cutting through the tape-shaped member, the tape-retaining member moving away from the abutment portion subsequent to a returning operation of the cutter blade for moving away from the tape-shaped member.
According to this preferred embodiment, when cutting operation is started, the tape-retaining member is slid in a manner interlocked with the lever operation of the manual operation lever, to hold the tape-shaped member between the same and the abutment portion prior to the advancing operation of the cutter for cutting through the tape-shaped member. Then, the cutter is slidingly moved to cut through the tape-shaped member. Further, after completion of the cutting operation, the cutter starts returning operation in advance of that of the tape-retaining member. This makes it possible to suppress deflection of the tape-shaped member caused by the cutting operation of the cutter to thereby allow the cutter to cut through the tape-shaped member with stability.
Preferably, the tape-retaining member is supported in a manner slidable relative to the cutter holder in a state urged toward the abutment portion.
According to this preferred embodiment, it is possible to simplify the construction of the cutter and component parts associated therewith to cause the tape-retaining member to be interlocked with the manual operation lever. More specifically, when the manual operation lever is operated, the tape-retaining member is slid to hold the tape-shaped member between the same and the cutter holder. Then, the cutter holder is further slid in the direction of cutting operation in a manner compressing the spring interposed between the same and the tape-retaining member, to cause the cutter blade to start cutting into the tape-shaped member.
Preferably, the tape-retaining member is arranged at a location downstream with respect to a direction of feed of the tape-shaped member, and outward of the cutter blade.
According to this preferred embodiment, the tape-shaped member is cut, at a position inward of a flutterable portion thereof downstream of the cutter blade, with the flutterable portion being retained, which enables the tape-shaped member to be linearly cut with increased stability. Further, since the cutter blade is protected from external access by the tape-retaining member, consistently from the start of the cutting operation to the completion thereof, it is also possible to enhance the safety of the tape exit and its vicinity.
The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.